/* CDATAReader.java                                                NanoXML/Java
 *
 * $Revision: 1.3 $
 * $Date: 2002/01/04 21:03:28 $
 * $Name: RELEASE_2_2_1 $
 *
 * This file is part of NanoXML 2 for Java.
 * Copyright (C) 2000-2002 Marc De Scheemaecker, All Rights Reserved.
 *
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from the
 * use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 *  1. The origin of this software must not be misrepresented; you must not
 *     claim that you wrote the original software. If you use this software in
 *     a product, an acknowledgment in the product documentation would be
 *     appreciated but is not required.
 *
 *  2. Altered source versions must be plainly marked as such, and must not be
 *     misrepresented as being the original software.
 *
 *  3. This notice may not be removed or altered from any source distribution.
 */

package net.n3.nanoxml;

import java.io.IOException;
import java.io.Reader;

/**
 * This reader reads data from another reader until the end of a CDATA section
 * (]]&gt;) has been encountered.
 * 
 * @author Marc De Scheemaecker
 * @version $Name: RELEASE_2_2_1 $, $Revision: 1.3 $
 */
class CDATAReader extends Reader {

	/**
	 * The encapsulated reader.
	 */
	private IXMLReader reader;

	/**
	 * Saved char.
	 */
	private char savedChar;

	/**
	 * True if the end of the stream has been reached.
	 */
	private boolean atEndOfData;

	/**
	 * Creates the reader.
	 * 
	 * @param reader
	 *            the encapsulated reader
	 */
	CDATAReader(IXMLReader reader) {
		this.reader = reader;
		this.savedChar = 0;
		this.atEndOfData = false;
	}

	/**
	 * Cleans up the object when it's destroyed.
	 */
	protected void finalize() throws Throwable {
		this.reader = null;
		super.finalize();
	}

	/**
	 * Reads a block of data.
	 * 
	 * @param buffer
	 *            where to put the read data
	 * @param offset
	 *            first position in buffer to put the data
	 * @param size
	 *            maximum number of chars to read
	 * 
	 * @return the number of chars read, or -1 if at EOF
	 * 
	 * @throws java.io.IOException
	 *             if an error occurred reading the data
	 */
	public int read(char[] buffer, int offset, int size) throws IOException {
		int charsRead = 0;

		if (this.atEndOfData) {
			return -1;
		}

		if ((offset + size) > buffer.length) {
			size = buffer.length - offset;
		}

		while (charsRead < size) {
			char ch = this.savedChar;

			if (ch == 0) {
				ch = this.reader.read();
			} else {
				this.savedChar = 0;
			}

			if (ch == ']') {
				char ch2 = this.reader.read();

				if (ch2 == ']') {
					char ch3 = this.reader.read();

					if (ch3 == '>') {
						this.atEndOfData = true;
						break;
					}

					this.savedChar = ch2;
					this.reader.unread(ch3);
				} else {
					this.reader.unread(ch2);
				}
			}
			buffer[charsRead] = ch;
			charsRead++;
		}

		if (charsRead == 0) {
			charsRead = -1;
		}

		return charsRead;
	}

	/**
	 * Skips remaining data and closes the stream.
	 * 
	 * @throws java.io.IOException
	 *             if an error occurred reading the data
	 */
	public void close() throws IOException {
		while (!this.atEndOfData) {
			char ch = this.savedChar;

			if (ch == 0) {
				ch = this.reader.read();
			} else {
				this.savedChar = 0;
			}

			if (ch == ']') {
				char ch2 = this.reader.read();

				if (ch2 == ']') {
					char ch3 = this.reader.read();

					if (ch3 == '>') {
						break;
					}

					this.savedChar = ch2;
					this.reader.unread(ch3);
				} else {
					this.reader.unread(ch2);
				}
			}
		}

		this.atEndOfData = true;
	}

}
